CN113764615A - Positive electrode and electrochemical device containing same - Google Patents
Positive electrode and electrochemical device containing same Download PDFInfo
- Publication number
- CN113764615A CN113764615A CN202111056345.5A CN202111056345A CN113764615A CN 113764615 A CN113764615 A CN 113764615A CN 202111056345 A CN202111056345 A CN 202111056345A CN 113764615 A CN113764615 A CN 113764615A
- Authority
- CN
- China
- Prior art keywords
- positive electrode
- lithium
- electrolyte
- conducting polymer
- composite
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 239000002131 composite material Substances 0.000 claims abstract description 107
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims abstract description 80
- 229910052744 lithium Inorganic materials 0.000 claims abstract description 80
- 239000002322 conducting polymer Substances 0.000 claims abstract description 77
- 229920001940 conductive polymer Polymers 0.000 claims abstract description 77
- 239000003792 electrolyte Substances 0.000 claims abstract description 58
- 239000011267 electrode slurry Substances 0.000 claims abstract description 9
- HBBGRARXTFLTSG-UHFFFAOYSA-N Lithium ion Chemical compound [Li+] HBBGRARXTFLTSG-UHFFFAOYSA-N 0.000 claims description 49
- 229910001416 lithium ion Inorganic materials 0.000 claims description 48
- 239000006256 anode slurry Substances 0.000 claims description 37
- 229920000642 polymer Polymers 0.000 claims description 30
- -1 polyethylene Polymers 0.000 claims description 23
- 239000002033 PVDF binder Substances 0.000 claims description 15
- 229920002981 polyvinylidene fluoride Polymers 0.000 claims description 15
- 229920001610 polycaprolactone Polymers 0.000 claims description 10
- 239000004632 polycaprolactone Substances 0.000 claims description 10
- 239000010416 ion conductor Substances 0.000 claims description 9
- 239000002202 Polyethylene glycol Substances 0.000 claims description 8
- 229920001223 polyethylene glycol Polymers 0.000 claims description 8
- 239000004014 plasticizer Substances 0.000 claims description 7
- 229920002239 polyacrylonitrile Polymers 0.000 claims description 7
- 150000003839 salts Chemical class 0.000 claims description 7
- 239000004698 Polyethylene Substances 0.000 claims description 6
- 229920000573 polyethylene Polymers 0.000 claims description 6
- 229920003171 Poly (ethylene oxide) Polymers 0.000 claims description 5
- 229920003229 poly(methyl methacrylate) Polymers 0.000 claims description 5
- 239000004926 polymethyl methacrylate Substances 0.000 claims description 5
- WNXJIVFYUVYPPR-UHFFFAOYSA-N 1,3-dioxolane Chemical compound C1COCO1 WNXJIVFYUVYPPR-UHFFFAOYSA-N 0.000 claims description 4
- XNWFRZJHXBZDAG-UHFFFAOYSA-N 2-METHOXYETHANOL Chemical compound COCCO XNWFRZJHXBZDAG-UHFFFAOYSA-N 0.000 claims description 4
- OIFBSDVPJOWBCH-UHFFFAOYSA-N Diethyl carbonate Chemical compound CCOC(=O)OCC OIFBSDVPJOWBCH-UHFFFAOYSA-N 0.000 claims description 4
- 239000004793 Polystyrene Substances 0.000 claims description 4
- JBTWLSYIZRCDFO-UHFFFAOYSA-N ethyl methyl carbonate Chemical compound CCOC(=O)OC JBTWLSYIZRCDFO-UHFFFAOYSA-N 0.000 claims description 4
- 239000002608 ionic liquid Substances 0.000 claims description 4
- 229910003002 lithium salt Inorganic materials 0.000 claims description 4
- 159000000002 lithium salts Chemical class 0.000 claims description 4
- 229920000515 polycarbonate Polymers 0.000 claims description 4
- 239000004417 polycarbonate Substances 0.000 claims description 4
- RUOJZAUFBMNUDX-UHFFFAOYSA-N propylene carbonate Chemical compound CC1COC(=O)O1 RUOJZAUFBMNUDX-UHFFFAOYSA-N 0.000 claims description 4
- IAHFWCOBPZCAEA-UHFFFAOYSA-N succinonitrile Chemical compound N#CCCC#N IAHFWCOBPZCAEA-UHFFFAOYSA-N 0.000 claims description 4
- ZUHZGEOKBKGPSW-UHFFFAOYSA-N tetraglyme Chemical compound COCCOCCOCCOCCOC ZUHZGEOKBKGPSW-UHFFFAOYSA-N 0.000 claims description 4
- OQMIRQSWHKCKNJ-UHFFFAOYSA-N 1,1-difluoroethene;1,1,2,3,3,3-hexafluoroprop-1-ene Chemical group FC(F)=C.FC(F)=C(F)C(F)(F)F OQMIRQSWHKCKNJ-UHFFFAOYSA-N 0.000 claims description 3
- 239000004743 Polypropylene Substances 0.000 claims description 3
- 239000004372 Polyvinyl alcohol Substances 0.000 claims description 3
- UCKMPCXJQFINFW-UHFFFAOYSA-N Sulphide Chemical compound [S-2] UCKMPCXJQFINFW-UHFFFAOYSA-N 0.000 claims description 3
- 229920000747 poly(lactic acid) Polymers 0.000 claims description 3
- 239000004626 polylactic acid Substances 0.000 claims description 3
- 229920001155 polypropylene Polymers 0.000 claims description 3
- 229920002223 polystyrene Polymers 0.000 claims description 3
- 229920002689 polyvinyl acetate Polymers 0.000 claims description 3
- 239000011118 polyvinyl acetate Substances 0.000 claims description 3
- 229920002451 polyvinyl alcohol Polymers 0.000 claims description 3
- 229920000915 polyvinyl chloride Polymers 0.000 claims description 3
- 239000004800 polyvinyl chloride Substances 0.000 claims description 3
- WDXYVJKNSMILOQ-UHFFFAOYSA-N 1,3,2-dioxathiolane 2-oxide Chemical compound O=S1OCCO1 WDXYVJKNSMILOQ-UHFFFAOYSA-N 0.000 claims description 2
- VAYTZRYEBVHVLE-UHFFFAOYSA-N 1,3-dioxol-2-one Chemical compound O=C1OC=CO1 VAYTZRYEBVHVLE-UHFFFAOYSA-N 0.000 claims description 2
- SJHAYVFVKRXMKG-UHFFFAOYSA-N 4-methyl-1,3,2-dioxathiolane 2-oxide Chemical compound CC1COS(=O)O1 SJHAYVFVKRXMKG-UHFFFAOYSA-N 0.000 claims description 2
- NIXOWILDQLNWCW-UHFFFAOYSA-M Acrylate Chemical compound [O-]C(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-M 0.000 claims description 2
- KMTRUDSVKNLOMY-UHFFFAOYSA-N Ethylene carbonate Chemical compound O=C1OCCO1 KMTRUDSVKNLOMY-UHFFFAOYSA-N 0.000 claims description 2
- 239000002227 LISICON Substances 0.000 claims description 2
- 239000002228 NASICON Substances 0.000 claims description 2
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 claims description 2
- IEJIGPNLZYLLBP-UHFFFAOYSA-N dimethyl carbonate Chemical compound COC(=O)OC IEJIGPNLZYLLBP-UHFFFAOYSA-N 0.000 claims description 2
- PGRMNXHYAZYNPG-UHFFFAOYSA-N fluoro hydrogen carbonate Chemical compound OC(=O)OF PGRMNXHYAZYNPG-UHFFFAOYSA-N 0.000 claims description 2
- 239000002223 garnet Substances 0.000 claims description 2
- 159000000003 magnesium salts Chemical class 0.000 claims description 2
- 125000000956 methoxy group Chemical group [H]C([H])([H])O* 0.000 claims description 2
- PYLWMHQQBFSUBP-UHFFFAOYSA-N monofluorobenzene Chemical compound FC1=CC=CC=C1 PYLWMHQQBFSUBP-UHFFFAOYSA-N 0.000 claims description 2
- 159000000000 sodium salts Chemical class 0.000 claims description 2
- ZQCQTPBVJCWETB-UHFFFAOYSA-N 4-fluoro-1,3-dioxol-2-one Chemical compound FC1=COC(=O)O1 ZQCQTPBVJCWETB-UHFFFAOYSA-N 0.000 claims 1
- 230000005540 biological transmission Effects 0.000 abstract description 7
- 150000002500 ions Chemical class 0.000 abstract description 5
- 238000009987 spinning Methods 0.000 description 114
- 239000000243 solution Substances 0.000 description 99
- 239000007787 solid Substances 0.000 description 98
- 238000002156 mixing Methods 0.000 description 51
- 238000000034 method Methods 0.000 description 42
- 238000001035 drying Methods 0.000 description 30
- 238000010041 electrostatic spinning Methods 0.000 description 29
- 239000002002 slurry Substances 0.000 description 27
- 239000011248 coating agent Substances 0.000 description 23
- 238000000576 coating method Methods 0.000 description 23
- 239000007774 positive electrode material Substances 0.000 description 17
- SECXISVLQFMRJM-UHFFFAOYSA-N N-Methylpyrrolidone Chemical compound CN1CCCC1=O SECXISVLQFMRJM-UHFFFAOYSA-N 0.000 description 16
- 239000011230 binding agent Substances 0.000 description 15
- 239000006258 conductive agent Substances 0.000 description 15
- 239000005518 polymer electrolyte Substances 0.000 description 15
- 239000002243 precursor Substances 0.000 description 15
- 239000007788 liquid Substances 0.000 description 13
- WEVYAHXRMPXWCK-UHFFFAOYSA-N Acetonitrile Chemical compound CC#N WEVYAHXRMPXWCK-UHFFFAOYSA-N 0.000 description 12
- ZMXDDKWLCZADIW-UHFFFAOYSA-N N,N-Dimethylformamide Chemical compound CN(C)C=O ZMXDDKWLCZADIW-UHFFFAOYSA-N 0.000 description 12
- 238000002360 preparation method Methods 0.000 description 12
- 230000008569 process Effects 0.000 description 12
- 238000003756 stirring Methods 0.000 description 12
- 238000005096 rolling process Methods 0.000 description 11
- 239000007784 solid electrolyte Substances 0.000 description 11
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 10
- 238000000280 densification Methods 0.000 description 10
- 239000011888 foil Substances 0.000 description 10
- 239000000463 material Substances 0.000 description 10
- 229910045601 alloy Inorganic materials 0.000 description 9
- 239000000956 alloy Substances 0.000 description 9
- 239000002904 solvent Substances 0.000 description 9
- IAZDPXIOMUYVGZ-UHFFFAOYSA-N Dimethylsulphoxide Chemical compound CS(C)=O IAZDPXIOMUYVGZ-UHFFFAOYSA-N 0.000 description 8
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 8
- 229920005569 poly(vinylidene fluoride-co-hexafluoropropylene) Polymers 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 229910013716 LiNi Inorganic materials 0.000 description 6
- 229910052782 aluminium Inorganic materials 0.000 description 6
- GELKBWJHTRAYNV-UHFFFAOYSA-K lithium iron phosphate Chemical compound [Li+].[Fe+2].[O-]P([O-])([O-])=O GELKBWJHTRAYNV-UHFFFAOYSA-K 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 239000000758 substrate Substances 0.000 description 6
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 239000012528 membrane Substances 0.000 description 5
- 239000010936 titanium Substances 0.000 description 5
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 4
- 229910012820 LiCoO Inorganic materials 0.000 description 4
- PWHULOQIROXLJO-UHFFFAOYSA-N Manganese Chemical compound [Mn] PWHULOQIROXLJO-UHFFFAOYSA-N 0.000 description 4
- FXHOOIRPVKKKFG-UHFFFAOYSA-N N,N-Dimethylacetamide Chemical compound CN(C)C(C)=O FXHOOIRPVKKKFG-UHFFFAOYSA-N 0.000 description 4
- WYURNTSHIVDZCO-UHFFFAOYSA-N Tetrahydrofuran Chemical compound C1CCOC1 WYURNTSHIVDZCO-UHFFFAOYSA-N 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
- QHGJSLXSVXVKHZ-UHFFFAOYSA-N dilithium;dioxido(dioxo)manganese Chemical compound [Li+].[Li+].[O-][Mn]([O-])(=O)=O QHGJSLXSVXVKHZ-UHFFFAOYSA-N 0.000 description 4
- 229910002804 graphite Inorganic materials 0.000 description 4
- 239000010439 graphite Substances 0.000 description 4
- 239000011777 magnesium Substances 0.000 description 4
- 229910052759 nickel Inorganic materials 0.000 description 4
- 239000002994 raw material Substances 0.000 description 4
- 229910052727 yttrium Inorganic materials 0.000 description 4
- SBLRHMKNNHXPHG-UHFFFAOYSA-N 4-fluoro-1,3-dioxolan-2-one Chemical compound FC1COC(=O)O1 SBLRHMKNNHXPHG-UHFFFAOYSA-N 0.000 description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 description 3
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 3
- 239000006230 acetylene black Substances 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 229910052733 gallium Inorganic materials 0.000 description 3
- 229910052738 indium Inorganic materials 0.000 description 3
- 229910052746 lanthanum Inorganic materials 0.000 description 3
- QSZMZKBZAYQGRS-UHFFFAOYSA-N lithium;bis(trifluoromethylsulfonyl)azanide Chemical compound [Li+].FC(F)(F)S(=O)(=O)[N-]S(=O)(=O)C(F)(F)F QSZMZKBZAYQGRS-UHFFFAOYSA-N 0.000 description 3
- MCVFFRWZNYZUIJ-UHFFFAOYSA-M lithium;trifluoromethanesulfonate Chemical compound [Li+].[O-]S(=O)(=O)C(F)(F)F MCVFFRWZNYZUIJ-UHFFFAOYSA-M 0.000 description 3
- 229910052749 magnesium Inorganic materials 0.000 description 3
- 229910052748 manganese Inorganic materials 0.000 description 3
- 239000005486 organic electrolyte Substances 0.000 description 3
- 229920000620 organic polymer Polymers 0.000 description 3
- 229920006254 polymer film Polymers 0.000 description 3
- 229910052712 strontium Inorganic materials 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 description 2
- 229910018632 Al0.05O2 Inorganic materials 0.000 description 2
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 229910009515 Li1.5Al0.5Ti1.5(PO4)3 Inorganic materials 0.000 description 2
- 229910013872 LiPF Inorganic materials 0.000 description 2
- 101150058243 Lipf gene Proteins 0.000 description 2
- 239000004721 Polyphenylene oxide Substances 0.000 description 2
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 2
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 2
- PNUGDRJNKILROY-UHFFFAOYSA-N [C].[Si].[Li] Chemical compound [C].[Si].[Li] PNUGDRJNKILROY-UHFFFAOYSA-N 0.000 description 2
- 239000011149 active material Substances 0.000 description 2
- 239000013543 active substance Substances 0.000 description 2
- 229910052787 antimony Inorganic materials 0.000 description 2
- 239000002041 carbon nanotube Substances 0.000 description 2
- 229910021393 carbon nanotube Inorganic materials 0.000 description 2
- 229910052804 chromium Inorganic materials 0.000 description 2
- 239000011651 chromium Substances 0.000 description 2
- 238000001523 electrospinning Methods 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 150000003949 imides Chemical class 0.000 description 2
- APFVFJFRJDLVQX-UHFFFAOYSA-N indium atom Chemical compound [In] APFVFJFRJDLVQX-UHFFFAOYSA-N 0.000 description 2
- 229910003480 inorganic solid Inorganic materials 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- FZLIPJUXYLNCLC-UHFFFAOYSA-N lanthanum atom Chemical compound [La] FZLIPJUXYLNCLC-UHFFFAOYSA-N 0.000 description 2
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 2
- 238000004519 manufacturing process Methods 0.000 description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 2
- 229910052814 silicon oxide Inorganic materials 0.000 description 2
- CIOAGBVUUVVLOB-UHFFFAOYSA-N strontium atom Chemical compound [Sr] CIOAGBVUUVVLOB-UHFFFAOYSA-N 0.000 description 2
- YLQBMQCUIZJEEH-UHFFFAOYSA-N tetrahydrofuran Natural products C=1C=COC=1 YLQBMQCUIZJEEH-UHFFFAOYSA-N 0.000 description 2
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- BTBUEUYNUDRHOZ-UHFFFAOYSA-N Borate Chemical compound [O-]B([O-])[O-] BTBUEUYNUDRHOZ-UHFFFAOYSA-N 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 description 1
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- GYHNNYVSQQEPJS-UHFFFAOYSA-N Gallium Chemical compound [Ga] GYHNNYVSQQEPJS-UHFFFAOYSA-N 0.000 description 1
- 229910006194 Li1+xAlxGe2-x(PO4)3 Inorganic materials 0.000 description 1
- 229910006196 Li1+xAlxGe2−x(PO4)3 Inorganic materials 0.000 description 1
- 229910006210 Li1+xAlxTi2-x(PO4)3 Inorganic materials 0.000 description 1
- 229910006212 Li1+xAlxTi2−x(PO4)3 Inorganic materials 0.000 description 1
- 229910009297 Li2S-P2S5 Inorganic materials 0.000 description 1
- 229910009311 Li2S-SiS2 Inorganic materials 0.000 description 1
- 229910009228 Li2S—P2S5 Inorganic materials 0.000 description 1
- 229910009225 Li2S—P2S5—GeS2 Inorganic materials 0.000 description 1
- 229910009433 Li2S—SiS2 Inorganic materials 0.000 description 1
- 229910011244 Li3xLa2/3-xTiO3 Inorganic materials 0.000 description 1
- 229910011245 Li3xLa2/3−xTiO3 Inorganic materials 0.000 description 1
- 229910011671 Li4-xGe1-xPxS4 Inorganic materials 0.000 description 1
- 229910011572 Li4−xGe1−xPxS4 Inorganic materials 0.000 description 1
- 229910011201 Li7P3S11 Inorganic materials 0.000 description 1
- 229910015013 LiAsF Inorganic materials 0.000 description 1
- 229910013075 LiBF Inorganic materials 0.000 description 1
- 229910010710 LiFePO Inorganic materials 0.000 description 1
- 229910015645 LiMn Inorganic materials 0.000 description 1
- 229910014689 LiMnO Inorganic materials 0.000 description 1
- 229910013385 LiN(SO2C2F5)2 Inorganic materials 0.000 description 1
- 229910015872 LiNi0.8Co0.1Mn0.1O2 Inorganic materials 0.000 description 1
- 229910012097 LiSbF Inorganic materials 0.000 description 1
- 229910000572 Lithium Nickel Cobalt Manganese Oxide (NCM) Inorganic materials 0.000 description 1
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-L Malonate Chemical compound [O-]C(=O)CC([O-])=O OFOBLEOULBTSOW-UHFFFAOYSA-L 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910021543 Nickel dioxide Inorganic materials 0.000 description 1
- 229910006180 NixCoyAl1-x-yO2 Inorganic materials 0.000 description 1
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical compound CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- PFYQFCKUASLJLL-UHFFFAOYSA-N [Co].[Ni].[Li] Chemical compound [Co].[Ni].[Li] PFYQFCKUASLJLL-UHFFFAOYSA-N 0.000 description 1
- YCOASTWZYJGKEK-UHFFFAOYSA-N [Co].[Ni].[W] Chemical compound [Co].[Ni].[W] YCOASTWZYJGKEK-UHFFFAOYSA-N 0.000 description 1
- QTHKJEYUQSLYTH-UHFFFAOYSA-N [Co]=O.[Ni].[Li] Chemical compound [Co]=O.[Ni].[Li] QTHKJEYUQSLYTH-UHFFFAOYSA-N 0.000 description 1
- NRJJZXGPUXHHTC-UHFFFAOYSA-N [Li+].[O--].[O--].[O--].[O--].[Zr+4].[La+3] Chemical compound [Li+].[O--].[O--].[O--].[O--].[Zr+4].[La+3] NRJJZXGPUXHHTC-UHFFFAOYSA-N 0.000 description 1
- KFDQGLPGKXUTMZ-UHFFFAOYSA-N [Mn].[Co].[Ni] Chemical compound [Mn].[Co].[Ni] KFDQGLPGKXUTMZ-UHFFFAOYSA-N 0.000 description 1
- ZYXUQEDFWHDILZ-UHFFFAOYSA-N [Ni].[Mn].[Li] Chemical compound [Ni].[Mn].[Li] ZYXUQEDFWHDILZ-UHFFFAOYSA-N 0.000 description 1
- NKLLZZNEDKQOOB-UHFFFAOYSA-N [O-2].[Mg+2].[Ti+4].[Ni+2].[Li+] Chemical compound [O-2].[Mg+2].[Ti+4].[Ni+2].[Li+] NKLLZZNEDKQOOB-UHFFFAOYSA-N 0.000 description 1
- FBDMTTNVIIVBKI-UHFFFAOYSA-N [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] Chemical compound [O-2].[Mn+2].[Co+2].[Ni+2].[Li+] FBDMTTNVIIVBKI-UHFFFAOYSA-N 0.000 description 1
- 238000005054 agglomeration Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- 229910052788 barium Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- JCXGWMGPZLAOME-UHFFFAOYSA-N bismuth atom Chemical compound [Bi] JCXGWMGPZLAOME-UHFFFAOYSA-N 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- ZADPBFCGQRWHPN-UHFFFAOYSA-N boronic acid Chemical compound OBO ZADPBFCGQRWHPN-UHFFFAOYSA-N 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000003575 carbonaceous material Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 229910017052 cobalt Inorganic materials 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 239000000306 component Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 239000008358 core component Substances 0.000 description 1
- 210000001787 dendrite Anatomy 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 150000004985 diamines Chemical class 0.000 description 1
- 238000009792 diffusion process Methods 0.000 description 1
- OKVJWADVFPXWQD-UHFFFAOYSA-N difluoroborinic acid Chemical compound OB(F)F OKVJWADVFPXWQD-UHFFFAOYSA-N 0.000 description 1
- 238000007599 discharging Methods 0.000 description 1
- 229910052732 germanium Inorganic materials 0.000 description 1
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 description 1
- 229910021389 graphene Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 239000003273 ketjen black Substances 0.000 description 1
- 229910000664 lithium aluminum titanium phosphates (LATP) Inorganic materials 0.000 description 1
- MHCFAGZWMAWTNR-UHFFFAOYSA-M lithium perchlorate Chemical group [Li+].[O-]Cl(=O)(=O)=O MHCFAGZWMAWTNR-UHFFFAOYSA-M 0.000 description 1
- 229910001486 lithium perchlorate Inorganic materials 0.000 description 1
- 229910001496 lithium tetrafluoroborate Inorganic materials 0.000 description 1
- XKLXIRVJABJBLQ-UHFFFAOYSA-N lithium;2-(trifluoromethyl)-1h-imidazole-4,5-dicarbonitrile Chemical compound [Li].FC(F)(F)C1=NC(C#N)=C(C#N)N1 XKLXIRVJABJBLQ-UHFFFAOYSA-N 0.000 description 1
- IGILRSKEFZLPKG-UHFFFAOYSA-M lithium;difluorophosphinate Chemical compound [Li+].[O-]P(F)(F)=O IGILRSKEFZLPKG-UHFFFAOYSA-M 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 230000005012 migration Effects 0.000 description 1
- 238000013508 migration Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 238000000465 moulding Methods 0.000 description 1
- 239000007773 negative electrode material Substances 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 230000010287 polarization Effects 0.000 description 1
- 229920000570 polyether Polymers 0.000 description 1
- 229920006380 polyphenylene oxide Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 229910052706 scandium Inorganic materials 0.000 description 1
- 238000001878 scanning electron micrograph Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 239000002210 silicon-based material Substances 0.000 description 1
- 239000006104 solid solution Substances 0.000 description 1
- 229910052596 spinel Inorganic materials 0.000 description 1
- 239000011029 spinel Substances 0.000 description 1
- 239000002203 sulfidic glass Substances 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- 125000003396 thiol group Chemical class [H]S* 0.000 description 1
- 239000011366 tin-based material Substances 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 238000009461 vacuum packaging Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 239000008096 xylene Substances 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
- 239000011701 zinc Substances 0.000 description 1
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/13—Electrodes for accumulators with non-aqueous electrolyte, e.g. for lithium-accumulators; Processes of manufacture thereof
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
- H01M4/00—Electrodes
- H01M4/02—Electrodes composed of, or comprising, active material
- H01M4/64—Carriers or collectors
- H01M4/66—Selection of materials
- H01M4/665—Composites
- H01M4/667—Composites in the form of layers, e.g. coatings
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/10—Energy storage using batteries
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- Chemical & Material Sciences (AREA)
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- Chemical Kinetics & Catalysis (AREA)
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- Composite Materials (AREA)
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- Battery Electrode And Active Subsutance (AREA)
Abstract
The invention discloses a positive electrode and an electrochemical device containing the same, wherein a composite positive electrode sheet comprises a current collector, and a first positive electrode layer, a second positive electrode layer and a third positive electrode layer which are coated on the surface of the current collector, wherein the first positive electrode layer close to the current collector comprises 70-90% of positive electrode slurry and 10-30% of lithium-conducting polymer; the second positive electrode layer comprises 50-70% of positive electrode slurry and 30-50% of lithium conducting polymer; the third positive electrode layer comprises 30-50% of positive electrode slurry and 50-70% of lithium conducting polymer; the lithium conducting polymer in each layer is present in the form of a continuous phase. The composite positive plate contains the three-dimensional lithium conduction channel, and solves the problems that lithium conduction in the positive electrode is difficult and the lithium conduction channel is not uniformly distributed in the solid-state battery, so that the resistance of the positive electrode and the solid-state electrolyte interface can be obviously reduced, the lithium conduction capability of the positive plate and the transmission efficiency of internal ions are improved, and the specific capacity and the specific energy of the battery are improved.
Description
Technical Field
The invention belongs to the technical field of electrochemical devices, and particularly relates to a positive electrode and an electrochemical device containing the same.
Background
Lithium ion batteries have been rapidly developed in the fields of notebooks, mobile phones, digital products, etc. because of their excellent characteristics of small size, light weight, high specific energy, no pollution, small self-discharge, long life, etc. Nowadays, the application of high-energy-density and high-power lithium ion batteries to the field of new energy vehicles is becoming a core technology, but higher requirements are provided for the structure and performance of the lithium ion batteries, and new challenges are faced to the key materials of the lithium ion batteries. At present, the industrialization of lithium ion batteries taking graphite as a negative electrode is difficult to meet the increasing demand of high specific energy. The solid electrolyte has higher mechanical strength, excellent compactness, certain capability of resisting the growth of lithium dendrites, and no characteristics of easy volatilization, flammability, explosiveness and the like of liquid organic electrolyte, so that the safety of the lithium ion battery in the use process can be greatly improved if the solid electrolyte is adopted to replace the liquid organic electrolyte to develop the all-solid lithium ion battery. However, the core components in solid-state lithium ion batteries are solid-solid contact between the solid electrolyte and the electrode, and thus the interface problem between the solid electrolyte and the electrode is mainly focused on: (1) the interface between the electrolyte and the positive electrode has poor contact wettability, so that the interface resistance is easily increased, and the interface transmission of lithium ions is influenced; (2) in the continuous circulation process of the lithium ion battery, the mutual diffusion of elements at the interface can cause the transmission capability of lithium ions at the interface to be reduced, so that the performance of the lithium ion battery is further deteriorated, and the water is recycled; (3) the solid electrolyte is different from the liquid organic electrolyte, and cannot infiltrate the pole piece to finish the migration of lithium ions, so that the lithium ion conducting capability of the traditional solid electrolyte composite anode is poor, and the lithium conducting capability of the bottom layer at the side, close to the current collector, of the anode with larger surface density is poorer, so that the lithium ions are more difficult to be inserted and removed. At present, the stability and adhesion between interfaces are mainly increased by adding a small amount of polymer electrolyte to the positive electrode, however, due to the influence of the active material, conductive agent and binder contained in the positive electrode, the polymer actually added to the positive electrode for conducting lithium is not uniformly distributed, and even agglomeration problem occurs, thereby affecting the conduction of lithium ions. And when the lithium ion battery is further assembled, the collapse of the structure in the positive pole piece can further accelerate the occurrence of interface side reaction along with the circulation of the battery, so that a lithium guide channel in the electrode is damaged, and further the capacity exertion of the battery is limited, the internal resistance of the battery is increased, and the cycle performance is deteriorated.
Therefore, it is desirable to provide a fast-charging solid-state positive electrode plate capable of improving the transmission of lithium ions in the solid-state positive electrode plate.
Disclosure of Invention
In order to solve the above problems, an object of the present invention is to provide a composite positive electrode sheet containing a polymer in a continuous phase form, which can significantly reduce the resistance at the interface between the positive electrode and the electrolyte and improve the lithium conductivity of the positive electrode sheet.
The invention further aims to provide a preparation method of the composite solid positive electrode capable of rapidly conducting lithium ions and having a good interface with a solid electrolyte. Compared with the traditional mode of directly adding the lithium conducting polymer into the positive electrode for mixed coating, the method for preparing the solid composite positive electrode with the laminated structure by electrostatic spinning is more uniform in performance, and the transport efficiency of ions and electrons is effectively improved; simple process, convenient operation, obvious effect and suitability for industrial application.
It is still another object of the present invention to provide an electrochemical device (e.g., a solid-state lithium ion battery) using the composite positive electrode, which has low internal resistance and good cycle performance.
In order to achieve the purpose, the invention adopts the technical scheme that:
a composite positive electrode sheet comprising a lithium conducting polymer in a continuous phase morphology.
According to the invention, the composite positive plate contains a three-dimensional polymer lithium-conducting conduction channel, namely a three-dimensional lithium-conducting and conducting network which is continuously communicated, and the lithium-conducting polymer in the composite positive plate exists in a continuous phase form.
According to the invention, the composite positive plate comprises a current collector and a positive electrode layer positioned on the surface of the current collector, wherein the positive electrode layer comprises a laminated structure, and the laminated structure comprises a lithium conducting polymer in a continuous phase state.
According to the invention, the composite positive plate comprises a current collector and a positive layer positioned on the surface of the current collector, wherein the positive layer comprises a laminated structure, the laminated structure contains three-dimensional polymer lithium conducting channels, namely three-dimensional lithium conducting and conducting networks which are continuously communicated, and lithium conducting polymers in each layer of the laminated structure exist in a continuous phase form. Further, the lithium conducting polymer located between the layers is also present in a continuous phase.
According to the invention, the positive plate comprises a current collector, and a first positive layer, a second positive layer and a third positive layer which are coated on the surface of the current collector, wherein the first positive layer close to the current collector comprises 70-90% of positive slurry and 10-30% of lithium conducting polymer; the second anode layer positioned above the first anode layer comprises 50-70% of anode slurry and 30-50% of lithium-conducting polymer; the third anode layer positioned above the second anode layer comprises 30-50% of anode slurry and 50-70% of lithium conducting polymer; the three anode layers contain three-dimensional polymer lithium conductive channels.
According to the present invention, the lithium conducting polymer in each of the three positive electrode layers is present in a continuous phase form. Further, the lithium conducting polymer located between the layers is also present in a continuous phase.
According to the present invention, the thickness of the first positive electrode layer may be 1 to 200 μm; exemplary are 1 μm, 10 μm, 50 μm, 100 μm, 200 μm.
According to the present invention, the thickness of the second positive electrode layer may be 1 to 200 μm; exemplary are 1 μm, 10 μm, 50 μm, 100 μm, 200 μm.
According to the present invention, the thickness of the third positive electrode layer may be 1 to 200 μm; exemplary are 1 μm, 10 μm, 50 μm, 100 μm, 200 μm.
According to the invention, the thickness of the whole composite positive plate can be 3-600 μm; exemplary are 3 μm, 10 μm, 50 μm, 100 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm.
According to the invention, the first positive electrode layer, the second positive electrode layer and the third positive electrode layer are coated on the surface of the current collector by an electrostatic spinning method from raw materials comprising positive electrode slurry and lithium-conducting polymer.
Wherein the positive electrode slurry includes a positive electrode active material, a conductive agent, and a binder.
Wherein the mass ratio of the positive electrode active material to the conductive agent to the binder is 80-98%: 0.5-10%: 0.5-10%; exemplary are 80:10:10, 90:5:6, 94:4:2, 95:0.5:4.5, 96:3:1, 98:1.5: 0.5.
Illustratively, the positive electrode active material contains one, two or more of lithium element, iron element, phosphorus element, cobalt element, manganese element, nickel element, and aluminum element; preferably, the positive electrode active material is doped and coated with one or two or more elements selected from aluminum, magnesium, titanium, zirconium, nickel, manganese, yttrium, lanthanum, strontium and the like.
For example, the positive electrode active material is selected from lithium iron phosphate and lithium cobaltate (LiCoO)2) The lithium-manganese-nickel ternary battery material, the lithium manganate, the nickel-cobalt-aluminum ternary battery material and the lithium-rich manganese-based material are at least one of the nickel-cobalt-manganese ternary battery material, the lithium manganate, the nickel-cobalt-aluminum ternary battery material and the lithium-rich manganese-based material, and the active material is formed by doping and coating one or two or more elements of aluminum, magnesium, titanium, zirconium, nickel, manganese, yttrium, lanthanum, strontium and the like.
Illustratively, the positive electrode active material is selected from lithium iron phosphate (LiFePO)4) Lithium cobaltate (LiCoO)2) Lithium nickel cobalt manganese oxide (LizNi)xCoyMn1-x-yO2Wherein: z is more than or equal to 0.95 and less than or equal to 1.05, x>0，y>0，x+y<1) Lithium manganate (LiMnO)2) Lithium nickel cobalt aluminate (Li)zNixCoyAl1-x-yO2Wherein: z is more than or equal to 0.95 and less than or equal to 1.05, x>0，y>0，0.8≤x+y<1) Nickel, nickelLithium cobalt manganese aluminate (Li)zNixCoyMnwAl1-x-y-wO2Wherein: z is more than or equal to 0.95 and less than or equal to 1.05, x>0，y>0，w>0，0.8≤x+y+w<1) Nickel cobalt aluminum tungsten material, lithium-rich manganese-based solid solution positive electrode material, lithium nickel cobalt oxide (LiNi)xCoyO2Wherein: x is the number of>0，y>0, x + y ═ 1), lithium nickel titanium magnesium oxide (LiNi)xTiyMgzO2Wherein: x is the number of>0，y>0，z>0, x + y + z ═ 1), lithium nickelate (Li)2NiO2) Spinel lithium manganate (LiMn)2O4) And nickel-cobalt-tungsten material, and the like.
According to the present invention, the conductive agent is selected from at least one of conductive carbon black (SP), ketjen black, acetylene black, Carbon Nanotubes (CNT), graphene, and flake graphite.
According to the invention, the binder is selected from at least one of polytetrafluoroethylene, polyvinylidene fluoride (PVDF) and polyvinylidene fluoride-hexafluoropropylene.
According to the invention, the lithium conducting polymer comprises a polymer, an electrolyte salt, a plasticizer and optionally an added or not added fast ion conductor.
According to the invention, the mass ratio of the polymer, the electrolyte salt, the plasticizer and the fast ion conductor is 50-80%: 10-40%: 1-10%: 0-10%, exemplary 50:40:10:0, 55:20:17:8, 60:30:5:5, 65:24:9:2, 68:18:7:7, 70:19:5:6, 80:10:1: 9.
According to the invention, the polymer is a polymer suitable for electrospinning, for example the polymer is selected from at least one of polymethylmethacrylate, polystyrene, polyvinyl chloride, polyethylene, polypropylene, polycarbonate, polyvinyl acetate, polyethylene oxide, polyacetimide, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene, polyvinyl alcohol, polyacrylonitrile, polylactic acid and Polycaprolactone (PCL).
According to the present invention, the electrolyte salt includes at least one of a lithium salt, a sodium salt, a magnesium salt, and an aluminum salt, preferably a lithium salt.
Illustratively, the lithium salt is lithium perchlorate (LiClO)4) Lithium hexafluorophosphate (LiPF)6) Lithium hexafluoroarsenate (LiAsF)6) Lithium tetrafluoroborate (LiBF)4) Lithium bis (oxalato) borate (LiBOB), lithium bis (oxalato) difluoroborate (LiDFOB), lithium bis (difluorosulfonimide) (LiFSI), lithium bis (trifluoromethylsulfonimide) (LiTFSI), lithium (trifluoromethylsulfonate) (LiCF)3SO3) Bis (malonic) boronic acid (LiBMB), lithium oxalatoborate malonate (LiMOB), lithium hexafluoroantimonate (LiSbF)6) Lithium difluorophosphate (LiPF)2O2) Lithium 4, 5-dicyano-2-trifluoromethylimidazole (LiDTI), lithium bis (trifluoromethylsulfonyl) imide (LiN (SO)2CF3)2)、LiN(SO2C2F5)2、LiC(SO2CF3)3And LiN (SO)2F)2One, two or more.
According to the invention, the plasticizer is selected from at least one of methoxy polyethylene glycol acrylate, polyethylene glycol methyl ether methacrylate, succinonitrile, ethylene carbonate, propylene carbonate, vinylene carbonate, ethylene sulfite, propylene sulfite, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, fluoro carbonate, tetraethylene glycol dimethyl ether, 1,3 dioxolane, fluorobenzene, fluoro ethylene carbonate, ionic liquid and the like.
According to the invention, the fast ion conductor may be a combination of one or more of a perovskite type electrolyte, an anti-perovskite type electrolyte, a Garnet type electrolyte, a NASICON type electrolyte, a LISICON type electrolyte, a sulphide electrolyte.
Illustratively, the perovskite-type electrolyte is Li3xLa2/3-xTiO3Wherein: x is more than 0.04 and less than 0.17.
Illustratively, the anti-perovskite electrolyte is Li3-n(OHn) Cl (n is more than or equal to 0.83 and less than or equal to 2) and Li3-n(OHn)Br(1≤n≤2)。
Illustratively, the garnet-type electrolyte is a lithium lanthanum zirconium oxide electrolyte and Al, Ga, Fe, Ge, Ca, Ba, Sr, Y, Nb, Ta, W, Sb element doped derivatives thereof; preferably Li7-nLa3Zr2-nTanO12、Li7-nLa3Zr2-nNbnO12Or Li6.4- xLa3Zr2-xTaxAl0.2O12(ii) a Wherein: n is more than or equal to 0 and less than or equal to 0.6; x is 0.2 to 0.5.
Illustratively, the NASICON-type electrolyte is Li1+xTi2-xMx(PO4)3(M ═ Al, Cr, Ga, Fe, Sc, In, Lu, Y, La), preferably Li1+xAlxTi2-x(PO4)3(LATP) (x is more than or equal to 0.2 and less than or equal to 0.5) or Li1+xAlxGe2-x(PO4)3(LAGP)(0.4≤x≤0.5)。
Illustratively, the LISICON-type electrolyte is Li4-xGe1-xPxS4(x ═ 0.4 or x ═ 0.6).
Illustratively, the sulfide solid electrolyte is selected from Li2S-SiS2、Li2S-P2S5、Li2S-P2S5-GeS2、Li7P3S11And Li6PS5And X (X ═ Cl, Br, I) is at least one.
The invention also provides an electrochemical device which comprises the composite positive plate.
According to the present invention, the electrochemical device is, for example, a lithium ion battery; specifically, the lithium ion battery is a solid-state lithium ion battery.
According to the invention, the solid-state lithium ion battery can be a button battery, a die battery, a pouch battery or an aluminum-case battery.
According to the invention, the lithium ion battery further comprises an electrolyte.
According to the invention, in the lithium ion battery, the composite positive plate and the electrolyte are in an integral structure.
The invention has the beneficial effects that:
(1) the composite positive plate contains the lithium conducting polymer in a continuous phase form, and further contains a three-dimensional polymer lithium conducting channel, namely a three-dimensional lithium conducting and conducting network which is continuously communicated, so that the design can obviously reduce the resistance of a positive electrode and an electrolyte interface and improve the lithium conducting capacity of the positive plate. Specifically, the composite positive plate provided by the invention has a continuous through three-dimensional lithium conducting and conducting network, and an ion transmission channel is smooth, so that the problems that lithium conducting in the positive electrode is difficult and the lithium conducting channel is not uniformly distributed in the solid-state battery are solved, the resistance of the positive electrode and the solid-state electrolyte interface can be obviously reduced, and the lithium conducting capacity of the positive plate is further improved.
(2) The composite positive plate can greatly reduce the concentration polarization in the electrode when discharging with high load capacity and high multiplying power, thereby effectively improving the transmission efficiency of ions in the solid-state battery pole piece and further improving the specific capacity and specific energy of the battery.
(3) The composite positive plate has the advantages of simple preparation process, convenient operation and obvious effect, and is suitable for industrial application. Specifically, the composite positive plate is obtained by uniformly coating the raw materials containing the positive slurry and the lithium-conducting polymer on the current collector by an electrostatic spinning method. Compared with the traditional mode of directly adding the lithium-conducting polymer into the positive electrode for mixing and coating, the lithium-conducting polymer in the laminated structure composite positive electrode sheet prepared by electrostatic spinning is more uniformly distributed, so that the transmission efficiency of lithium ions and electrons is effectively improved.
(4) Electrochemical devices (such as lithium ion batteries, particularly solid lithium ion batteries) assembled by the composite positive plate prepared by the invention have low internal resistance, and show higher cycle stability and coulombic efficiency in continuous charge-discharge cycles.
Drawings
Fig. 1 is a schematic structural diagram of the composite positive plate of the present invention.
Fig. 2 is a schematic structural diagram of a lithium ion battery manufactured in example 2 of the present invention.
Fig. 3 is an SEM micrograph of the surface of the composite positive electrode prepared in example 3.
Fig. 4 is a first charge-discharge curve diagram of the lithium ion battery assembled by the composite positive electrode sheet in example 4.
Detailed Description
As described above, the present invention provides a composite positive electrode sheet having a special structure, and based on the positive electrode sheet, the present invention also provides a method for producing the composite positive electrode sheet, the method comprising the steps of: and covering the surface of a current collector with the positive slurry and a lithium-conducting polymer as raw materials by an electrostatic spinning method to prepare the composite positive plate. Compared with the traditional mode of directly adding the lithium conducting polymer into the positive electrode for mixed coating, the composite positive electrode plate prepared by electrostatic spinning is more uniform in performance, and the transport efficiency of ions and electrons is effectively improved; simple process, convenient operation, obvious effect and suitability for industrial application.
According to the present invention, the positive electrode slurry and the lithium conducting polymer have the selection and the amount ratio as described above.
According to the invention, the method for preparing the composite positive plate comprises the following steps:
s1: uniformly mixing a polymer, an electrolyte salt, a plasticizer and an optionally added fast ion conductor in a solvent, and ultrasonically dispersing to prepare a lithium-conducting polymer spinning solution;
s2: mixing and stirring a positive active substance, a conductive agent and a binder in a solvent to prepare positive slurry;
s3: mixing the lithium-conducting polymer spinning solution and the anode slurry according to different proportions to prepare a plurality of anode layer spinning solutions (for example, a first anode layer spinning solution, a second anode layer spinning solution and a third anode layer spinning solution);
s4: spinning a plurality of positive pole layer spinning solutions (such as a first positive pole layer spinning solution, a second positive pole layer spinning solution and a third positive pole layer spinning solution) onto the current-collecting foil by an electrostatic spinning method in sequence;
s5: and drying, rolling and compacting to obtain the composite positive plate.
According to the present invention, in step S1, the solvent is at least one of Acetonitrile (ACN), N-methylpyrrolidone (NMP), Dimethylformamide (DMF), Dimethylacetamide (DMAC), Dimethylsulfoxide (DMSO), ethanol, acetone, dichloromethane, chloroform, xylene, and Tetrahydrofuran (THF).
According to the invention, in step S1, the lithium-conducting polymer spinning solution has a solid content of 5-40%, illustratively 5%, 10%, 20%, 30%, 40%.
According to the invention, in step S2, the solvent is N-methylpyrrolidone (NMP).
According to the invention, in step S2, the solid content of the positive electrode slurry is 20-80%, and is illustratively 20%, 30%, 40%, 50%, 60%, 70%, 80%.
According to the invention, in step S3, the first positive electrode layer spinning solution comprises 70% to 90% of positive electrode slurry (solid) and 10% to 30% of lithium conducting polymer;
the second anode layer spinning solution comprises 50-70% of anode slurry and 30-50% of lithium-conducting polymer;
the third anode layer spinning solution comprises 30-50% of anode slurry and 50-70% of lithium conducting polymer.
According to the invention, in step S4, the distance between the injection needle and the receiving plate in the electrostatic spinning method may be 5-40 cm, preferably 10-30 cm; exemplary are 5cm, 10cm, 14cm, 20cm, 30cm, 40 cm.
According to the invention, in the step S4, in the electrostatic spinning process, the moving speed of the current collector is 0.1-4 m/min, preferably 0.5-2 m/min; illustrative are 0.1m/min, 0.5m/min, 0.8m/min, 1m/min, 1.2m/min, 2m/min, 3m/min, 4 m/min.
According to the invention, in the step S4, in the electrostatic spinning process, a high-voltage power supply is 5-40 kV, preferably 10-25 kV; exemplary are 5KV, 10KV, 15KV, 20KV, 25KV, 30KV, 40 KV.
According to the invention, in step S5, the drying temperature can be 60-120 ℃; exemplary are 60 deg.C, 80 deg.C, 100 deg.C, 120 deg.C.
As described above, the present invention also provides an electrochemical device including the composite positive electrode sheet described above.
According to the invention, the electrochemical device is, for example, a lithium ion battery, in particular an all solid-state lithium ion battery.
According to the invention, the lithium ion battery further comprises a negative electrode.
According to the present invention, the negative electrode active material in the negative electrode is, for example, at least one selected from the group consisting of carbon materials, metal bismuth, metal lithium, metal copper, metal indium, nitrides, lithium-based alloys, magnesium-based alloys, indium-based alloys, boron-based materials, silicon-based materials, tin-based materials, antimony-based alloys, gallium-based alloys, germanium-based alloys, aluminum-based alloys, lead-based alloys, zinc-based alloys, oxides of titanium, oxides of iron, oxides of chromium, oxides of molybdenum, and phosphides, and the like.
According to the invention, the lithium ion battery further comprises an electrolyte, which is located between the composite positive and negative electrodes.
Preferably, the electrolyte may be a solid electrolyte. Further, the solid electrolyte may be one of an inorganic solid electrolyte and an organic polymer electrolyte, and is preferably an organic polymer electrolyte.
Illustratively, the inorganic solid electrolyte may be an oxide electrolyte or a sulfide electrolyte.
Illustratively, the organic polymer electrolyte is selected from the group consisting of polymethylmethacrylate, polystyrene, polyvinyl chloride, polyethylene, polypropylene, polycarbonate, polyvinyl acetate, polyethylene oxide, polyacetimide, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene, polyvinyl alcohol, polyacrylonitrile, polylactic acid, Polycaprolactone (PCL), polycarbonate, polyether, polyethylene glycol, polyphenylene oxide, polyethylene diamine, polyethylene glycol thiol, and the like, and copolymerized derivatives thereof.
According to the invention, the electrolyte and the composite positive plate are in an integral structure.
According to the invention, the lithium-conducting polymer spinning solution is subjected to electrostatic spinning on the surface of the composite positive plate to prepare the electrolyte and the composite positive plate with an integrated structure.
According to the present invention, the lithium ion battery may be at least one of a button battery, a mold battery, a pouch battery, and an aluminum can battery.
The invention also provides a preparation method of the lithium ion battery, which comprises the steps of sequentially assembling the composite positive plate, the optional electrolyte and the negative electrode together, and carrying out vacuum packaging to obtain the lithium ion battery.
Specifically, the composite electrode plate and the electrolyte exist in an integrated structure form, and the composite electrode plate is prepared by a method comprising the following steps:
preparing the composite electrode slice by adopting the method for preparing the composite electrode slice;
carrying out electrolyte coating on the surface of the composite positive plate and/or carrying out electrostatic spinning on the lithium-conducting polymer spinning solution on the surface of the composite positive plate to prepare a composite positive electrode-electrolyte integrated structure;
then the lithium ion battery is assembled with the cathode and is packaged in vacuum to obtain the lithium ion battery.
The technical solution of the present invention will be described in more detail with reference to specific examples. It is to be understood that the following examples are only illustrative and explanatory of the present invention and should not be construed as limiting the scope of the present invention. All the technologies realized based on the above-mentioned contents of the present invention are covered in the protection scope of the present invention.
Unless otherwise indicated, the raw materials and reagents used in the following examples are all commercially available products or can be prepared by known methods.
The test methods for each example and comparative example are as follows:
1. AC impedance test at room temperature
The method for testing the alternating current impedance of the lithium ion battery comprises the following steps:
the test was carried out using the Shanghai Chenghua CHI600E electrochemical workstation, with the parameters set: the amplitude is 10mV, and the frequency range is 0.1 Hz-3 MHz.
2. Cycle life testing of lithium ion batteries
The test instrument is Wuhan blue battery test equipment;
and (3) testing conditions are as follows: the specific capacity exertion, the cycle number and the first turn coulombic efficiency are measured under the conditions of 25 ℃ and 0.2C/0.2C.
Example 1
The composite positive electrode structure provided by the invention is shown in figure 1, and the composite positive electrode comprises a solid composite positive electrode layer I and a current collector layer II. Wherein: the solid composite positive electrode layer comprises a first positive electrode layer (fifth) close to the current collector layer (second), a second positive electrode layer (fourth) above the first positive electrode layer and a third positive electrode layer (third) above the second positive electrode layer (fourth).
The method for preparing the composite anode and the solid-state battery by the electrostatic spinning method comprises the following steps:
s1: polyvinylidene fluoride, lithium bistrifluoromethylsulfonyl imide (LiTFSI), polyethylene glycol methyl ether methacrylate and Li6.6La3Zr1.6Ta0.4O12Uniformly mixing the fast ion conductor in DMAC according to the mass ratio of 70:20:6:4, and ultrasonically dispersing to prepare a lithium-conducting polymer spinning solution 1 with the solid content of 11%;
s2: the positive electrode active material lithium cobaltate (LiCoO)2) Preparing slurry with the solid content of 70% by using a conductive agent acetylene black and a binder PVDF in NMP according to the mass ratio of 94:4:2, and uniformly mixing and stirring to obtain anode slurry 2;
s3: mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 24:76 to prepare a first anode layer spinning solution A; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 40:60 to prepare a second anode layer spinning solution B; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the proportion of the solid content of 65:35 to prepare a third anode layer spinning solution C; .
S4: mounting an Al foil current collector on a receiving plate, adjusting the distance between an injector and the receiving plate to be 15cm, adjusting the moving speed of the current collector to be 0.8m/min, setting a high-voltage power supply to be 16kV, setting the internal spinning temperature of electrostatic spinning equipment to be 45 ℃, adding a first positive pole layer spinning solution A into the injector, and controlling the thickness of a first positive pole layer after spinning and drying to be 30 mu m; then, an injector containing a second anode layer spinning solution B is used, the same step is carried out, and the thickness of the dried second anode layer is controlled to be 10 micrometers; and finally, spinning by using the spinning solution C of the third positive electrode layer, and controlling the thickness of the third positive electrode layer after drying the solvent to be 10 microns.
S5: after drying for 12h at 80 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: preparation of solid-state batteries: further coating the lithium-conducting polymer spinning solution 1 on the surface of the positive plate rolled in the step S5 (to ensure good connection of the interface), wherein the thickness of the electrolyte membrane is 30 μm;
s7: and (5) assembling the solid composite anode and the PVDF integrated structure prepared in the step (S6) with a metal lithium cathode to form the all-solid battery.
Comparative example 1
The method for preparing the composite anode and the solid-state battery by the electrostatic spinning method comprises the following steps:
s1: polyvinylidene fluoride, lithium bistrifluoromethylsulfonyl imide (LiTFSI), polyethylene glycol methyl ether methacrylate and Li6.6La3Zr1.6Ta0.4O12Uniformly mixing the fast ion conductor in DMAC according to the mass ratio of 70:20:6:4, and ultrasonically dispersing to prepare a lithium-conducting polymer spinning solution 1 with the solid content of 11%;
s2: the positive electrode active material lithium cobaltate (LiCoO)2) Preparing slurry with the solid content of 70% by using a conductive agent acetylene black and a binder PVDF in NMP according to the mass ratio of 94:4:2, and uniformly mixing and stirring to obtain a precursor liquid 2;
s3: mixing the precursor solution 1 and the precursor solution 2 according to the solid content of 24:76 to prepare a positive electrode layer spinning solution 3;
s4: mounting an Al foil current collector on a receiving plate, adjusting the distance between an injector and the receiving plate to be 15cm, adjusting the moving speed of the current collector to be 0.8m/min, setting the internal spinning temperature of electrostatic spinning equipment to be 45 ℃, adding a spinning solution 3 of a positive electrode layer into the injector, and controlling the thickness of a first positive electrode layer after spinning and drying to be 30 mu m;
s5: after drying for 12h at 80 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: preparation of solid-state batteries: further coating the lithium-conducting polymer spinning solution 1 on the surface of the positive plate rolled in the step S5 (to ensure good connection of the interface), wherein the thickness of the electrolyte membrane is 30 μm;
s7: and (5) assembling the solid composite anode and the PVDF integrated structure prepared in the step (S6) with a metal lithium cathode to form the all-solid battery.
Example 2
The solid-state battery structure provided by the invention is shown in fig. 2 and comprises a solid-state composite positive electrode layer, a current collector layer, a solid-state electrolyte layer and a negative electrode layer, wherein the solid-state composite positive electrode layer comprises a first positive electrode layer arranged on one side close to the current collector layer, a second positive electrode layer arranged above the first positive electrode layer and a third positive electrode layer arranged above the second positive electrode layer, and the solid-state electrolyte layer is positioned between the solid-state composite positive electrode layer and the negative electrode layer.
The method for preparing the composite solid positive electrode and the solid battery by the electrostatic spinning method comprises the following steps:
s1: polyacrylonitrile, lithium trifluoromethanesulfonate (LiCF)3SO3) Diethyl carbonate and succinonitrile are uniformly mixed in DMSO according to the mass ratio of 68:18:7:7 and ultrasonically dispersed to prepare a lithium conducting polymer spinning solution 1 with the solid content of 8%;
s2: preparing a slurry with the solid content of 62% from a positive active material lithium iron phosphate, a conductive agent SP and a binder polyvinylidene fluoride-hexafluoropropylene in NMP according to the mass ratio of 96:3:1, and uniformly mixing and stirring to obtain a positive slurry 2;
s3: mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 28:72 to prepare a first anode layer spinning solution A; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 34:66 ratio to prepare a second anode layer spinning solution B; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 66:34 to prepare a third anode layer spinning solution C;
s4: mounting an Al foil current collector on a receiving plate, adjusting the distance between an injector and the receiving plate to be 14cm, adjusting the moving speed of the current collector to be 1.2m/min, setting the high-voltage power supply to be 15kV, setting the internal spinning temperature of electrostatic spinning equipment to be room temperature, adding a first positive electrode layer spinning solution A into the injector, and controlling the thickness of a first positive electrode layer after spinning and drying to be 40 mu m; then, an injector containing a second anode layer spinning solution B is used for spinning in the same step, and the thickness of the dried second anode layer is controlled to be 10 microns; and finally, spinning by using the spinning solution C of the third positive electrode layer, and controlling the thickness of the third positive electrode layer after drying the solvent to be 20 microns.
S5: after drying for 24 hours at 80 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: the preparation of the polymer electrolyte adopts the traditional process: coating the lithium-conducting polymer spinning solution 1 on a release film substrate to form a film, wherein the thickness of the finally prepared polymer electrolyte film is 30 micrometers;
s7: and (4) assembling the solid composite positive electrode prepared in the step S5, the polymer electrolyte prepared in the step S6 and the silicon oxide negative electrode into an all-solid battery.
Comparative example 2
S1: polyacrylonitrile, lithium trifluoromethanesulfonate (LiCF3 SO)3) Diethyl carbonate and succinonitrile are uniformly mixed in DMSO according to the mass ratio of 68:18:7:7 and ultrasonically dispersed to prepare a polymer spinning solution 1 with the solid content of 8%;
s2: preparing a slurry with the solid content of 62% from a positive active material lithium iron phosphate, a conductive agent SP and a binder polyvinylidene fluoride-hexafluoropropylene in NMP according to the mass ratio of 96:3:1, and uniformly mixing and stirring to obtain a positive slurry 2;
s3: mixing the polymer spinning solution 1 and the anode slurry 2 according to the proportion of the solid content of 28:72 to prepare an anode layer spinning solution 3;
s4: mounting an Al foil current collector on a receiving plate, adjusting the distance between an injector and the receiving plate to be 14cm, adjusting the moving speed of the current collector to be 1.2m/min, setting the high-voltage power supply to be 15kV, setting the internal spinning temperature of electrostatic spinning equipment to be room temperature, firstly adding a positive electrode layer spinning solution 3 into the injector, and controlling the thickness of a positive electrode layer after spinning and drying to be 40 mu m;
s5: after drying for 24 hours at 80 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: the preparation of the polymer electrolyte adopts the traditional process: coating the lithium-conducting polymer spinning solution 1 on a release film substrate to form a film, wherein the thickness of the finally prepared electrolyte film is 30 micrometers;
s7: and (4) assembling the solid composite positive electrode prepared in the step S5, the polymer electrolyte prepared in the step S6 and the silicon oxide negative electrode into an all-solid battery.
Example 3
The method for preparing the composite solid positive electrode and the solid battery by the electrostatic spinning method comprises the following steps:
s1: uniformly mixing polyvinylpyrrolidone, polymethyl methacrylate, lithium oxalyldifluoroborate and fluoroethylene carbonate in DMF according to the mass ratio of 55:20:17:8, and ultrasonically dispersing to prepare a lithium conducting polymer spinning solution 1 with the solid content of 13%;
s2: LiNi as positive electrode active material0.8Co0.15Al0.05O2Preparing slurry with the solid content of 60% by using a conductive agent SP and a binder PVDF in NMP according to the mass ratio of 94:4:2, and uniformly mixing and stirring to obtain anode slurry 2;
s3: mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 16:84 to prepare a first anode layer spinning solution A; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 42:58 to prepare a second anode layer spinning solution B; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 70:30 to prepare a third anode layer spinning solution C;
s4: mounting an Al foil current collector on a receiving plate, adjusting the distance between an injector and the receiving plate to be 18cm, adjusting the moving speed of the current collector to be 0.6m/min, setting the high-voltage power supply to be 18kV, setting the internal spinning temperature of electrostatic spinning equipment to be 45 ℃, adding a first positive pole layer spinning solution A into the injector, and controlling the thickness of a first positive pole layer after spinning and drying to be 80 mu m; then, an injector containing a second anode layer spinning solution B is used, the same step is carried out, and the thickness of the dried second anode layer is controlled to be 40 mu m; and finally, spinning by using the spinning solution C of the third positive electrode layer, and controlling the thickness of the third positive electrode layer after drying the solvent to be 20 microns.
S5: after drying for 24 hours at 80 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: the preparation of the polymer electrolyte adopts the traditional process: coating the lithium-conducting polymer spinning solution 1 on a release film substrate to form a film, wherein the thickness of the finally prepared electrolyte film is 50 micrometers;
s7: and (4) assembling the solid composite positive electrode prepared in the step S5, the polymer electrolyte prepared in the step S6 and the metallic lithium negative electrode into an all-solid battery.
Fig. 3 shows the SEM microstructure of the surface of the composite positive electrode obtained in step S5 of this embodiment. As can be seen from the figure: the composite anode prepared by the invention has a compact surface, and the lithium conducting polymer and the anode active substance in the composite anode are uniformly dispersed and exist in a continuous phase form, so that a continuous through three-dimensional polymer lithium conducting and conducting channel is formed, the resistance of the interface of the anode and an electrolyte can be reduced, and the lithium conducting capacity of an anode plate is improved.
Comparative example 3
A method for producing a composite solid positive electrode and a solid battery by an electrospinning method, comprising the steps of S1: uniformly mixing polyvinylpyrrolidone, polymethyl methacrylate, lithium oxalyldifluoroborate and fluoroethylene carbonate in DMF according to the mass ratio of 55:20:17:8, and ultrasonically dispersing to prepare a lithium conducting polymer spinning solution 1 with the solid content of 13%;
s2: LiNi as positive electrode active material0.8Co0.15Al0.05O2Preparing slurry with the solid content of 60% by using a conductive agent SP and a binder PVDF in NMP according to the mass ratio of 94:4:2, and uniformly mixing and stirring to obtain anode slurry 2;
s3: mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 16:84 to prepare a first anode layer slurry A; mixing the polymer precursor liquid 1 and the anode slurry 2 according to the solid content of 42:58 to prepare a second anode layer slurry B; mixing the polymer precursor liquid 1 and the anode slurry 2 according to the solid content of 70:30 to prepare a third anode layer slurry C;
s4: coating the first anode layer slurry A on an Al foil current collector and drying to obtain a first anode layer with the thickness of 80 mu m; coating second positive electrode layer slurry B on the basis of the first positive electrode layer, drying and controlling the thickness of the dried second positive electrode layer to be 40 mu m; and then coating third positive electrode layer slurry C on the basis of the second positive electrode layer, drying and controlling the thickness of the dried third positive electrode layer to be 20 microns.
S5: after drying for 24 hours at 80 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: the preparation of the polymer electrolyte adopts the traditional process: coating the lithium-conducting polymer spinning solution 1 on a release film substrate to form a film, wherein the thickness of the finally prepared electrolyte film is 50 micrometers;
s7: and (4) assembling the solid composite positive electrode prepared in the step S5, the polymer electrolyte prepared in the step S6 and the metallic lithium negative electrode into an all-solid battery.
Example 4
The method for preparing the composite solid positive electrode and the solid battery by the electrostatic spinning method comprises the following steps:
s1: mixing polyoxyethylene, polycaprolactone, lithium bis (difluorosulfonimide) (LiFSI), propylene carbonate, ethyl methyl carbonate and Li1.5Al0.5Ti1.5(PO4)3Uniformly mixing and ultrasonically dispersing in ACN according to the mass ratio of 10:55:18:6:9:2 to prepare a lithium-conducting polymer spinning solution 1 with the solid content of 15%;
s2: LiNi as positive electrode active material0.8Co0.1Mn0.1O2Preparing slurry with the solid content of 60% by mass of a conductive agent SP and a binder PVDF in NMP according to the mass ratio of 96:3:1, and uniformly mixing and stirring to obtain anode slurry 2;
s3: mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the proportion of solid content of 16:84 to prepare a first anode layer spinning solution A; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the proportion of solid content of 42:58 to prepare a second anode layer spinning solution B; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 70:30 to prepare a third anode layer spinning solution C;
s4: mounting an Al foil current collector on a receiving plate, adjusting the distance between an injector and the receiving plate to be 12cm, adjusting the moving speed of the current collector to be 0.9m/min, setting a high-voltage power supply to be 16kV, setting the internal spinning temperature of electrostatic spinning equipment to be 30 ℃, adding a first positive pole layer spinning solution A into the injector, and controlling the thickness of a first positive pole layer after spinning and drying to be 50 mu m; then, an injector containing a second anode layer spinning solution B is used, the same step is carried out, and the thickness of the dried second anode layer is controlled to be 50 micrometers; and finally, spinning by using the spinning solution C of the third positive electrode layer, and controlling the thickness of the third positive electrode layer after drying the solvent to be 50 microns.
S5: after drying for 15h at 60 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: preparation of solid-state batteries: further coating the lithium-conducting polymer spinning solution 1 on the surface of the positive plate rolled in the step S5 (to ensure good connection of the interface), wherein the thickness of the electrolyte membrane is 60 μm;
s7: and (4) assembling the solid composite anode prepared in the step (S6) and the polyethylene oxide-polycaprolactone-based polymer film into an integral structure together with a graphite cathode to form the all-solid-state battery.
Fig. 4 is a first charge-discharge curve diagram of a lithium ion battery assembled by using the composite positive electrode sheet in this embodiment. As can be seen from the figure: a charge-discharge interval: 3-4.2V; charge-discharge multiplying power: at 0.2C/0.2C, the lithium ion battery prepared by the embodiment shows typical LiNi0.8Co0.1Mn0.1O2Capacity-voltage curve, gram capacity exertion is 206 mAh/g. This indicates that: the composite positive plate has excellent capacity exertion and good lithium-conducting performance.
Comparative example 4
The method for preparing the composite solid positive electrode and the solid battery by the electrostatic spinning method comprises the following steps:
s1: mixing polyoxyethylene, polycaprolactone, lithium bis (difluorosulfonimide) (LiFSI), propylene carbonate, ethyl methyl carbonate and Li1.5Al0.5Ti1.5(PO4)3Uniformly mixing the components in ACN according to the mass ratio of 10:55:18:6:9:2, and ultrasonically dispersing to prepare a polymer precursor liquid 1 with the solid content of 15%;
s2: LiNi as positive electrode active material0.8Co0.1Mn0.1O2Preparing slurry with the solid content of 60% by mass of a conductive agent SP and a binder PVDF in NMP according to the mass ratio of 96:3:1, and uniformly mixing and stirring to obtain anode slurry 2;
s3: mixing the polymer precursor liquid 1 and the anode slurry 2 according to the solid content of 16:84 to prepare a first anode layer precursor liquid A; mixing the polymer precursor liquid 1 and the anode slurry 2 according to the solid content of 42:58 to prepare a second anode layer precursor liquid B; mixing the polymer precursor liquid 1 and the anode slurry 2 according to the solid content of 70:30 to prepare a third anode layer precursor liquid C;
s4: coating the first anode layer slurry A on an Al foil current collector and drying to obtain a first anode layer with the thickness of 50 microns; coating second anode layer slurry B on the basis of the first anode layer, drying and controlling the thickness of the dried second anode layer to be 50 microns; then coating third anode layer slurry C on the basis of the second anode layer, drying and controlling the thickness of the dried third anode layer to be 50 microns;
s5: after drying for 15h at 60 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: preparation of solid-state batteries: further coating the lithium-conducting polymer spinning solution 1 on the surface of the positive plate rolled in the step S5 (to ensure good connection of the interface), wherein the thickness of the electrolyte membrane is 60 μm;
s7: and (4) assembling the solid composite anode prepared in the step (S6) and the polyethylene oxide-polycaprolactone-based polymer film into an integral structure together with a graphite cathode to form the all-solid-state battery.
Example 5
The method for preparing the composite solid positive electrode and the solid battery by the electrostatic spinning method comprises the following steps:
s1: polyacrylonitrile, polyvinylidene fluoride-hexafluoropropylene, lithium bis (trifluoromethylsulfonyl) imide (LiN (SO)2CF3)2) Uniformly mixing the ionic liquid and 1,3 dioxolane in NMP according to the mass ratio of 12:58:19:5:6, and ultrasonically dispersing to prepare a lithium conducting polymer spinning solution 1 with the solid content of 16%;
s2: preparing a slurry with the solid content of 62% from a positive active material lithium iron phosphate, a conductive agent SP and a binder polyvinylidene fluoride-hexafluoropropylene in NMP according to the mass ratio of 96:3:1, and uniformly mixing and stirring to obtain a positive slurry 2;
s3: mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content of 28:72 to prepare a first anode layer spinning solution A; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the solid content ratio of 34:66 to prepare a second anode layer spinning solution B; mixing the lithium-conducting polymer spinning solution 1 and the anode slurry 2 according to the proportion of the solid content of 66:34 to prepare a third anode layer spinning solution C;
s4: mounting an Al foil current collector on a receiving plate, adjusting the distance between an injector and the receiving plate to be 14cm, adjusting the moving speed of the current collector to be 1.2m/min, setting the high-voltage power supply to be 15kV, setting the internal spinning temperature of electrostatic spinning equipment to be room temperature, adding a first positive electrode layer spinning solution A into the injector, and controlling the thickness of a first positive electrode layer after spinning and drying to be 20 micrometers; then, an injector containing a second anode layer spinning solution B is used, the same step is carried out, and the thickness of the dried second anode layer is controlled to be 60 mu m; finally, spinning by using a third anode layer spinning solution C, and controlling the thickness of the dried solvent of the third anode layer to be 80 microns;
s5: after drying for 24 hours at 80 ℃, performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: the integrated molding process of the anode and the electrolyte is adopted: further spinning the lithium-conducting polymer spinning solution 1 on the solid-state composite positive plate substrate prepared in the step S5 by an electrostatic spinning method (the distance between the injector and the receiving plate is adjusted to be 14cm, the moving speed of the current collector is 1.2m/min, and the high-voltage power supply is 15kV), and measuring the thickness of an electrolyte membrane to be 30 mu m after drying to obtain an electrostatic spinning integrated positive electrode + electrolyte structure;
s7: and (5) assembling the solid composite anode and polyacrylonitrile-polyvinylidene fluoride-hexafluoropropylene polymer film integrated structure prepared in the step (S6) with the lithium silicon carbon cathode to form the all-solid battery.
Comparative example 5
The method for preparing the composite solid positive electrode and the solid battery by the electrostatic spinning method comprises the following steps:
s1: polyacrylonitrile, polyvinylidene fluoride-hexafluoropropylene, lithium bis (trifluoromethylsulfonyl) imide (LiN (SO)2CF3)2) Uniformly mixing the ionic liquid and 1,3 dioxolane in NMP according to the mass ratio of 12:58:19:5:6, and ultrasonically dispersing to prepare a lithium conducting polymer spinning solution 1 with the solid content of 16%;
s2: preparing a slurry with the solid content of 62% from a positive active material lithium iron phosphate, a conductive agent SP and a binder polyvinylidene fluoride-hexafluoropropylene in NMP according to the mass ratio of 96:3:1, and uniformly mixing and stirring to obtain a positive slurry 2;
s3: mixing the polymer precursor solution 1 and the anode slurry 2 according to the solid content of 28:72 to prepare a first anode layer spinning solution A; mixing the polymer precursor solution 1 and the anode slurry 2 according to the solid content ratio of 34:66 to prepare a second anode layer spinning solution B; mixing the polymer precursor solution 1 and the anode slurry 2 according to the proportion of the solid content of 66:34 to prepare a third anode layer spinning solution C;
s4: fully mixing and stirring a first positive pole layer spinning solution A, a second positive pole layer spinning solution B and a third positive pole layer spinning solution C to obtain a uniform solution, and coating on an Al current collector;
s5: after drying for 24 hours at 80 ℃, controlling the coating thickness to be 160 mu m, and then performing rolling densification on the composite anode to obtain the solid composite anode sheet;
s6: the preparation of the polymer electrolyte adopts the traditional process: coating the lithium-conducting polymer spinning solution 1 on a release film substrate to form a film, wherein the thickness of the finally prepared electrolyte film is 30 micrometers;
s7: and (4) assembling the solid composite positive electrode prepared in the step S5, the polymer electrolyte prepared in the step S6 and the lithium silicon carbon negative electrode into an all-solid battery.
Table 1 shows the gram capacity play ratio, internal resistance, cycle life, and coulombic efficiency at room temperature of the lithium ion batteries provided in examples 1 to 5 of the present invention and the comparative example.
TABLE 1
The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiment. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. A composite positive electrode sheet, characterized in that it comprises a lithium-conducting polymer in the form of a continuous phase.
2. The composite positive electrode sheet according to claim 1, wherein the composite positive electrode sheet contains three-dimensional polymer lithium conducting and conducting channels, and the lithium conducting polymer in the composite positive electrode sheet exists in a continuous phase form.
3. The composite positive electrode sheet according to claim 1, comprising a current collector and a positive electrode layer on the surface of the current collector, wherein the positive electrode layer comprises a layered structure comprising a lithium conducting polymer in a continuous phase.
4. The composite positive electrode sheet according to claim 3, which comprises a current collector and a positive electrode layer on the surface of the current collector, wherein the positive electrode layer comprises a layered structure containing three-dimensional polymer lithium conducting channels, and the lithium conducting polymer in each layer of the layered structure exists in a continuous phase.
5. The composite positive electrode sheet according to any one of claims 1 to 4, wherein the positive electrode sheet comprises a current collector and a first positive electrode layer, a second positive electrode layer and a third positive electrode layer coated on the surface of the current collector, and the first positive electrode layer on the side close to the current collector comprises 70% to 90% of positive electrode slurry and 10% to 30% of lithium conducting polymer; the second anode layer positioned above the first anode layer comprises 50-70% of anode slurry and 30-50% of lithium-conducting polymer; the third anode layer positioned above the second anode layer comprises 30-50% of anode slurry and 50-70% of lithium conducting polymer; the three positive electrode layers contain three-dimensional polymer lithium conductive channels; the lithium conducting polymer in each of the three positive electrode layers is in a continuous phase, and the lithium conducting polymer between the layers is also in a continuous phase.
6. The composite positive electrode sheet according to any one of claims 1 to 5, wherein the lithium-conducting polymer comprises a polymer, an electrolyte salt, a plasticizer and optionally an added or non-added fast ion conductor.
7. The composite positive electrode sheet according to claim 6, wherein the mass ratio of the polymer, the electrolyte salt, the plasticizer and the fast ion conductor is 50 to 80%: 10-40%: 1-10%: 0 to 10 percent;
and/or the polymer is selected from at least one of polymethyl methacrylate, polystyrene, polyvinyl chloride, polyethylene, polypropylene, polycarbonate, polyvinyl acetate, polyethylene oxide, polyacetimide, polyvinylidene fluoride, vinylidene fluoride-hexafluoropropylene, polyvinyl alcohol, polyacrylonitrile, polylactic acid and Polycaprolactone (PCL);
and/or the electrolyte salt comprises at least one of a lithium salt, a sodium salt, a magnesium salt and an aluminum salt;
and/or the plasticizer is selected from at least one of methoxy polyethylene glycol acrylate, polyethylene glycol methyl ether methacrylate, succinonitrile, ethylene carbonate, propylene carbonate, vinylene carbonate, ethylene sulfite, propylene sulfite, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, fluoro carbonate, tetraethylene glycol dimethyl ether, 1,3 dioxolane, fluorobenzene, fluoro ethylene carbonate, ionic liquid and the like;
and/or the fast ion conductor may be a combination of one or more of a perovskite type electrolyte, an anti-perovskite type electrolyte, a Garnet type electrolyte, a NASICON type electrolyte, a LISICON type electrolyte, a sulfide electrolyte.
8. An electrochemical device comprising the composite positive electrode sheet according to any one of claims 1 to 7.
9. The electrochemical device of claim 8, wherein the electrochemical device is a lithium ion battery;
and/or the lithium ion battery further comprises an electrolyte.
10. The electrochemical device according to claim 9, wherein the composite positive electrode sheet and the electrolyte are integrated in the lithium ion battery.
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| CN116265400A (en) * | 2021-12-17 | 2023-06-20 | 中国科学院过程工程研究所 | Preparation method of lithium battery positive electrode material, lithium battery positive electrode material and lithium battery |
| CN114695838A (en) * | 2022-03-28 | 2022-07-01 | 天能电池集团股份有限公司 | Lithium battery positive pole piece, preparation method thereof and lithium battery adopting positive pole piece |
| CN114695838B (en) * | 2022-03-28 | 2024-04-12 | 天能电池集团股份有限公司 | Positive electrode plate of lithium battery, preparation method of positive electrode plate and lithium battery adopting positive electrode plate |
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